New results help predict treatment response in colorectal cancerSeptember 17, 2008Genetic testing can identify a group of patients with advanced colorectal cancer who are likely to survive on average twice as long if treated with the drug cetuximab, late breaking results show. At the 33rd Congress of the European Society for Medical Oncology (ESMO) in Stockholm, Dr. Christos Karapetis from Flinders University in Australia reports on a genetic analysis of 394 patients who took part in a phase III study comparing the monoclonal antibody cetuximab with best supportive care. The latest analysis compared the effect of mutations in the K-Ras gene on overall survival and progression-free survival. The gene encodes a protein that is a key component of cellular signalling pathways, conveying extracellular growth signals from the cell surface to the nucleus. When growth factors bind to cell surface receptors, including epidermal growth factor receptor (EGFR), K-Ras is temporarily activated, facilitating regulated cell growth and proliferation. The K-Ras gene is mutated in up to 35% of colorectal cancers. These mutations keep K-Ras stuck in its active form, switching on signalling without the requirement for EGFR stimulation. Dr. Karapetis and colleagues found that patients with mutated forms of K-Ras had a median overall survival of 4.6 months when treated with cetuximab, and 4.5 moths with supportive care. In contrast, among those with wild-type forms, overall survival jumped to 9.5 months when treated with cetuximab, compared to 4.8 months with best supportive care. The results show that determining K-Ras mutation status should be considered a new standard of care for selecting patients for targeted therapies against EGFR, the authors say. Also at the congress, Professor Eric Van Cutsem from University Hospital Gasthuisberg, Leuven in Belgium will present data on the impact of K-Ras mutations from the Crystal study, in which patients were randomized to either the chemotherapy combination "FOLFIRI" or FOLFIRI plus cetuximab, in first line metastatic colorectal cancer. Professor Van Cutsem recently reported that the combination of cetuximab and FOLFIRI significantly improves progression free survival and response rate in patients with a K-Ras wild type. In Stockholm he will present new data on survival in the Crystal trial. "Overall survival in all patients included in the trial was identical in both treatment arms. There was however a strong trend towards a longer survival in patients with a K-Ras wild type tumor treated with cetuximab/FOLFIRI," he said. The median survival was 24.9 months for patients who received the cetuximab combination, versus 21.0 months (HR: 0.84). The overall survival results in patients with K-Ras mutant tumors did not differ in the two study arms. In another study, Dr. Miriam Koopman from the University Nijmegen Medical Centre St. Radboud in The Netherlands, reports that the number of tumor cells found circulating in the blood of patients with advanced colorectal cancer is another valuable predictor of survival. Her group studied 467 patients who were being treated within a prospective clinical trial (CAIRO2 of the Dutch Colorectal Cancer Group) with chemotherapy plus bevacizumab, with or without the addition of cetuximab. In each patient they measured levels of circulating tumor cells before treatment, and at different stages during treatment. "Circulating tumor cell (CTC) level might be an indicator of the aggressiveness of disease," Dr. Koopman explained. "Thus, a high CTC level before initiating therapy in metastatic colorectal cancer patients is an inferior prognostic factor in our study." The results show that the median progression-free survival time for patients with less than three CTC in every 7.5mL of blood was 10.5 months, compared to 8.2 months for those with three or more. Furthermore the median overall survival time for patients with less than three CTC in every 7.5mL of blood was 22.2 months, compared to 13.7 months for those with three or more. "In our study CTC in metastatic colorectal cancer patients proves to be an early prognostic marker," Dr. Koopman said. "Prospective trials are needed to investigate whether a change in therapy based on CTC is beneficial." European Society for Medical Oncology |
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| Related Colorectal Cancer Current Events and Colorectal Cancer News Articles 'Cross-talk' mechanism contributes to colorectal cancer Researchers at the University of Wisconsin-Madison School of Medicine and Public Health have identified a molecular mechanism that allows two powerful signaling pathways to interact and begin a process leading to colorectal tumors. African-Americans with colorectal cancer have poorer outcomes, lower survival rates New research published in the November issue of the Journal of the American College of Surgeons shows that African-American patients with colorectal cancer are more likely to be diagnosed with advanced disease and are less likely to undergo surgical procedures compared with Caucasians, suggesting that improvements in screening and rates of operation may reduce differences in colorectal cancer outcomes for African-Americans. Colon cancer screening more effective earlier in day, UCLA study finds The effectiveness of a screening colonoscopy may depend on the time of day it is performed. According to a new UCLA study, early-morning colonoscopies yielded more polyps per patient than later screenings, and fewer polyps were found hour by hour as the day progressed. 1 disease, not 1 demographic The Asian continent has nearly four billion people living in 47 different countries, and each of these groups has their own unique set of health issues. But when they come to the United States, they're often lumped into one large demographic: "Asian/Pacific Islander." Study shows unsedated colonoscopy for colorectal cancer screening well accepted by patients Researchers from Taiwan report in a new study that unsedated colonoscopy for primary colorectal cancer screening is well accepted in a majority of patients. M. D. Anderson redefines screening guidelines for breast, cervical and colorectal cancers Drawing on years of experience in cancer research and patient care, The University of Texas M. D. Anderson Cancer Center released today the most comprehensive, risk-based screening guidelines publicly available to date for breast, cervical and colorectal cancers. The bowels of infection Current research suggests that latent cytomegalovirus (CMV) infection may exacerbate inflammatory bowel disease (IBD). The related report by Onyeagocha et al, "Latent cytomegalovirus infection exacerbates experimental colitis," appears in the November 2009 issue of The American Journal of Pathology. How to Lower Costs, Waiting Times for Colonoscopies Colorectal cancer is a leading cause of cancer-related deaths in the United States, leading to over 50,000 fatalities every year. Excess body weight causes over 124,000 new cancers a year in Europe At least 124,000 new cancers in 2008 in Europe may have been caused by excess body weight, according to estimates from a new modelling study. Adding cetuximab to chemotherapy reduces advanced lung cancer death risk by 13 percent Patients with advanced non-small cell lung cancer who are given cetuximab (Erbitux) in addition to chemotherapy are 13% less likely to die than those who receive chemotherapy alone, regardless of which chemotherapy drug cocktail is used, new research finds. They also experience slower disease progression and an increased chance of tumour shrinkage. More Colorectal Cancer Current Events and Colorectal Cancer News Articles |
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